function cambiarTamano(){
    // Set specific variable to represent all iframe tags.
    var iFrames = document.getElementsByTagName('iframe');

    // Resize heights.
    function iResize()
    {
            // Iterate through all iframes in the page.
            for (var i = 0, j = iFrames.length; i < j; i++)
            {
                    // Set inline style to equal the body height of the iframed content.
                    iFrames[i].style.height = iFrames[i].contentWindow.document.body.offsetHeight + 'px';
            }
    }

    // Check if browser is Safari or Opera.
    if ($.browser.safari || $.browser.opera)
    {
            // Start timer when loaded.
            $('iframe').load(function()
                    {
                            setTimeout(iResize, 0);
                    }
            );

            // Safari and Opera need a kick-start.
            for (var i = 0, j = iFrames.length; i < j; i++)
            {
                    var iSource = iFrames[i].src;
                    iFrames[i].src = '';
                    iFrames[i].src = iSource;
            }
            alert('opera');
    }
    else
    {
            // For other good browsers.
            $('iframe').load(function()
                    {
                            // Set inline style to equal the body height of the iframed content.
                            this.style.height = this.contentWindow.document.body.offsetHeight + 'px';
                    }
            );
            alert('chorme');
    }
}